pesticide article

I think this discussion on the pesticide/cancer link article is a typical a
case of letting our bias get in the way of actual science.  This article
when googled leads to a wide variety of well-meaning sites which quote it as
a fact that "there is a positive link between NHL and Round-up."  I doubt
any of them have actually read the article, but they heard someone else say
that that is what the article proved.  Sadly, if you can access the article
via PubMed, which my UC Davis status allows me, you will find that the
research uncovered NO SUCH THING.  Unfortunately, people get a piece of
information they don't really understand, and because it fits their dogma
that 'all chemicals are bad', they jump on it and blow it up into something
it isn't.  
First, it should be noted that this 'case-controlled' study was conducted by
phone interviews and written surveys which are notoriously unreliable.
There was no actual collection of residues from homes or environments to
correlate the cases with real data.  No government-regulated application
sheets were accessed for the workers who were interviewed to assess real
levels of potential exposure.
Second, the class of chemicals that could be correlated positively was the
phenoxy-acetic acids (like 2,4-D and MCPA), an entirely different class of
chemicals than glyphosate with an entirely different mode of action and
chemical reaction to the environment. (with different break down products as
previously pointed out.)
Third, out of over 700 people interviewed in a region of Northern Sweden,
only four cases were exposed to glyphosate.  The study doesn't explain what
exposure means - what the level of exposure is, or if there is a difference
between levels.  This is probably because they are taking what people's
memories will give them.  Did these 4 drink it? Spill it on their skin?
Inhale the spray?  We just don't know.
Lastly, as with any scientific research, one paper does not a fact make.
There are many, many studies done constantly to find positive links between
chemical applications and cancer, and they are conducted much more
rigorously than this one was.  When a link to cancer is established, the
chemicals are removed from the approved list.  
It should also be pointed out that CORRELATION does not mean CAUSAL.  When
you deal with a group of people who have more than one factor in common, it
can be extremely difficult to sort out a cause-and-effect relationship,
since some other over-looked factor may be slanting the study (Did all these
Swedes drink Vodka?).  For this reason, I rarely take these surveys as
actual "controlled" studies, though they do make interesting launching
points for more rigorous scientific research.
	Well, that's my two bits.  And as for glyphosate: it's my favorite
chemical, though I use it sparingly and only when hand-weeding is
impractical.  If good science proves it harmful, I will mourn its passing
from my shelf.

Karrie Reid
Folsom Foothill Gardener
Zone 9
(and UC Davis Master's candidate in Horticulture and Agronomy)

<<attachment: winmail.dat>>

I think this discussion on the pesticide/cancer link article is a typical a
case of letting our bias get in the way of actual science.  This article
when googled leads to a wide variety of well-meaning sites which quote it as
a fact that "there is a positive link between NHL and Round-up."  I doubt
any of them have actually read the article, but they heard someone else say
that that is what the article proved.  Sadly, if you can access the article
via PubMed, which my UC Davis status allows me, you will find that the
research uncovered NO SUCH THING.  Unfortunately, people get a piece of
information they don't really understand, and because it fits their dogma
that 'all chemicals are bad', they jump on it and blow it up into something
it isn't.  
First, it should be noted that this 'case-controlled' study was conducted by
phone interviews and written surveys which are notoriously unreliable.
There was no actual collection of residues from homes or environments to
correlate the cases with real data.  No government-regulated application
sheets were accessed for the workers who were interviewed to assess real
levels of potential exposure.
Second, the class of chemicals that could be correlated positively was the
phenoxy-acetic acids (like 2,4-D and MCPA), an entirely different class of
chemicals than glyphosate with an entirely different mode of action and
chemical reaction to the environment. (with different break down products as
previously pointed out.)
Third, out of over 700 people interviewed in a region of Northern Sweden,
only four cases were exposed to glyphosate.  The study doesn't explain what
exposure means - what the level of exposure is, or if there is a difference
between levels.  This is probably because they are taking what people's
memories will give them.  Did these 4 drink it? Spill it on their skin?
Inhale the spray?  We just don't know.
Lastly, as with any scientific research, one paper does not a fact make.
There are many, many studies done constantly to find positive links between
chemical applications and cancer, and they are conducted much more
rigorously than this one was.  When a link to cancer is established, the
chemicals are removed from the approved list.  
It should also be pointed out that CORRELATION does not mean CAUSAL.  When
you deal with a group of people who have more than one factor in common, it
can be extremely difficult to sort out a cause-and-effect relationship,
since some other over-looked factor may be slanting the study (Did all these
Swedes drink Vodka?).  For this reason, I rarely take these surveys as
actual "controlled" studies, though they do make interesting launching
points for more rigorous scientific research.
	Well, that's my two bits.  And as for glyphosate: it's my favorite
chemical, though I use it sparingly and only when hand-weeding is
impractical.  If good science proves it harmful, I will mourn its passing
from my shelf.

Karrie Reid
Folsom Foothill Gardener
Zone 9
(and UC Davis Master's candidate in Horticulture and Agronomy)
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